Lysines residues impact Cdc42p stability. Stabilization of GTP-bound Cdc42p induces fMAPK activity in a Tec1p-dependent manner. (A) Levels of GFP-Cdc42p containing the indicated versions of Cdc42p. Wild-type cells (PC538) were grown in SD-URA at 30°C for 5 h (30°C) and shifted to 37°C for 2 h (37°C). See Fig. S1 A for details. (B) Wild-type cells (WT, PC538) and tec1Δ mutant (PC6102) expressing GFP-Cdc42p^Q61L+TD (Q61L+TD, PC7654). Scale bar, 10 µm. (C)tec1Δ cells (PC6102) expressing GFP-Cdc42p (PC6454, Cdc42), GFP-Cdc42p^Q61L (PC7458, Q61L) or GFP-Cdc42p^Q61L+TD (PC7654, Q61L+TD) were grown for 6 h in SD-URA media. See Fig. 3 F for details. (D) Halo formation in response to α-factor for wild-type cells (WT, PC6810) and the ste11Δ mutant (PC6604) expressing same plasmids as in C. Cells grown for 16 h in selective SD-URA media were spread on SD-URA media, and α-factor was spotted at two concentrations on the surface, 2 and 6 µM, to study cell-cycle arrest. Source data are available for this figure: SourceData FS3.